/* 去重方法1 */
{
    let arr = [1, 23, 2, 3, 2, 3, 33, 4]
    let m = {}
    let ret = []
    for (a of arr) {
        if (m[a] != 10086) {
            ret.push(a)
        }
        m[a] = 10086
    }
    console.log(ret)
}

/* 去重方法2 */
{
    let arr = [1, 23, 2, 3, 2, 3, 33, 4]
    let ret = []
    for (a of arr) {
        if (ret.indexOf(a) == -1) {
            ret.push(a)
        }
    }
    console.log(ret)
}


